CT及MRI在不典型脑脓肿诊断中的应用价值

CT and MRI diagnosis of atypical brain abscess

目的探讨CT和MRI对不典型脑脓肿的诊断价值。方法对23例经手术及临床抗炎治疗证实为不典型脑脓肿的CT和MRI表现进行回顾分析，18例行CT扫描，16例行MRI扫描。结果脓肿位于大脑半球21例，小脑半球2例，单房21例，多房2例，形态不规则形15例，椭圆形8例；CT平扫脓肿壁模糊不清4例；增强扫描CT显示脓肿壁厚薄不均11例，壁见结节样突起4例，壁环欠连续3例；MRI显示脓肿壁厚薄不均10例，壁见结节样突起4例，壁环不连续2例，5例脓肿临近脑膜见强化；13例脓腔在DWI上呈高信号，在ADC上呈低信号，7例^1H—MRS具有特征性的氨基酸峰。结论不典型脑脓肿的cT及MRI表现有一定特征，DWI及MRS对诊断是一个很好的补充并在不典型脑脓肿诊断上有重要的应用价值。

Objective To assess the value of CT and MRI for diagnosing atypical brain abscess. Methods CT（18） and MRI （16） of 23 patients with surgically confirmed atypical brain abscesses were analyzed retrospectively. Results The abscesses located in the cerebral （21） and cerebellar （2） hemispheres were uni- （21） or muhi-locular （2）, irregular （15） or oval （8） in shape. The abscess walls were ill-defined on the unenhanced CT （4）, uneven in thickness on contrast-enhanced CT （11）with nodular protrusions （4） and discontinuous walls （3）. MRI showed uneven abscess wall thickness （10）, mural nodules （4）, discontinuous walls （2）, and adjacent meningeal enhancement （5）. The abscess cavities were hyperintense on diffusion-weighted imaging with low apparent diffusion coefficients（13）. Proton MR spectroscopy showed characteristic amino acid peaks in 7 patients. Conclusions CT and MRI have characteristic features for diagnosing atypical brain abscesses.